Recommendations for weight loss

The National Institutes of Health reported that nearly two-thirds of U.S. adults were overweight or obese. Each year, countless studies investigate various weight-loss tactics, such as low-fat versus high-fat diets, whether it's beneficial to snack (or not) and the importance of exercise for weight loss and maintenance. Data from large groups whose members lost weight on their own, and kept it off, also has been analyzed to determine how they achieved success.

The latest studies conclude that a successful weight-loss plan is a mind/body undertaking that not only involves monitoring calorie intake and expenditure, but dealing with the psychological side of weight loss and habit change.

But what really works and what doesn't? These seven proven principles can increase your chances of weight-loss success now -- and for the long term.

1. Get mentally prepared before you start.

Kelly D. Brownell, Ph.D., a psychology professor at Yale University, recommends asking yourself two key questions before starting a weight-loss program: "Compared with the last time I dieted, how motivated am I now?" And, "Do I see myself being committed for the weeks, months or years it will take to reach my goal?"

"If you can honestly answer 'Very!' and 'Yes!,' you're ready to take on the challenge of weight loss," says Dr. Brownell. "If you're not mentally prepped before you dive into a diet, you're more likely to mount a halfhearted effort and suffer the inevitable consequence: regaining the weight."

If your motivation level needs a boost, list the negative aspects to staying at your present weight. These could include having increased health risks, low energy or not looking your best.

2. Don't aim to lose any more than 10 percent of your weight in six months.

Forget trying to be model thin or get down to what you weighed in high school. Set a more modest goal by cutting 3,500 to 7,000 calories (one to two pounds) per week from what you normally consume. Even those with life-threatening weight problems are advised to stick to that humble objective. Why?

"Most people aren't able to lose more than 10 percent of their weight," says Gary Foster, Ph.D., who is a faculty member of the Weight and Eating Disorders Program at the University of Pennsylvania School of Medicine. "Even if you could, studies suggest you'll be more likely to gain it back."

Losing so little over such a long time may seem like a small achievement, but it's not if you keep it off.

3. Include regular exercise in your weight-loss plan.

To lose weight, you must reduce your calorie intake. "Studies show exercise alone doesn't produce much weight loss," says Holly R. Wyatt, M.D., associate professor of medicine at the University of Colorado Health Sciences Center in Denver. Still, you should get in the habit of exercising while in the weight-loss phase of your diet because you'll need it when you move to weight maintenance. "In study after study, the people who exercise are the people who keep weight off long term," says Dr. Wyatt.

Indeed, in a study of 3,000 people who lost at least 30 pounds and kept the weight off for a year or more, 90 percent said exercise was the key to their weight maintenance, according to the National Weight Control Registry. The 2005 dietary guidelines from the U.S. Department of Agriculture recommend 30 to 60 minutes of moderate to vigorous exercise daily to help prevent weight gain, and 60 to 90 minutes daily to help you sustain weight loss.

4. Don't eliminate fat from your diet, but do watch how much you eat.

A calorie is still a calorie whether it comes from fat or carbohydrate or protein. Fats supply energy and essential fatty acids, and they help absorb the fat-soluble vitamins A, D, E and K and carotenoids. Fat contains 9 calories per gram; carbohydrates and proteins contain 4 calories per gram. So, eating 1 gram of fat gives you more calories than 1 gram of carbohydrate. Reducing the amount of fat you eat is one way to limit your overall calorie intake. Eating fat-free or reduced-fat foods isn't always the answer to weight loss, if you eat more of the reduced-fat food than you would of the regular item. For example, if you eat twice as many fat-free crackers as regular crackers, you have increased your overall calorie intake. Remember, just because a product is fat-free, it doesn't mean that it is "calorie-free." All calories count!

5. Avoid snacking.

According to a recent University of North Carolina survey and analysis of nationwide food consumption of more than 63,000 people, Americans' snack consumption has increased more than 50 percent over the last 20 years. Such "snackaholic" habits could be contributing to America's collective weight problem. Snackers eat the same amount at meals as nonsnackers, so they end up eating more total calories, according to studies by David Levitsky, Ph.D., professor of nutrition and psychology at Cornell University.

6. You can eat the foods you crave -- every now and then.

On special occasions -- say you really want the chocolate cake and ice cream at an office party -- go ahead and dig in. For her book Eating Thin for Life, Anne Fletcher, R.D., surveyed the diet habits of 208 people who lost an average of 64 pounds and kept it off, and found that successful weight losers don't deprive themselves of foods they crave or love.

"But they have control systems for tempting foods so they don't go overboard," says Ms. Fletcher.

7. Weigh yourself regularly.

To maintain weight loss, don't ignore your scale and go by other indicators, such as how well your jeans fit. Instead, play the numbers game and step on the scale once a week.

"A weekly weigh-in can accurately help you monitor your weight, so you realize when you're in relapse," says Dr. Wyatt. If you gain five pounds or more, she advises immediate action. Ask yourself what you've been doing lately that might have caused the weight gain, then make changes to lose those extra few pounds within the month.